1. Field of the Invention
The invention relates to a device, system and method for improving delivery of hemostatic material by the use of a vent cap.
2. Brief Description of the Related Art
A percutaneous needle biopsy of solid organs is one of the most common interventional medical procedures. Millions of percutaneous needle biopsies are performed annually in the United States and throughout the world. A percutaneous biopsy is a safe procedure which has supplanted a surgical biopsy for many indications, such as skin biopsy and liver biopsy.
Possible complications of a needle biopsy include bleeding at the biopsy site. The amount of bleeding is related to a number of factors including needle size, tissue sample size, patient's coagulation status, and the location of the biopsy site. Vascular organs such as the liver, a common biopsy target, may bleed significantly after a needle biopsy. To minimize bleeding from a biopsy site, small gauge needles are typically used. Small gauge needles, however, produce less satisfactory biopsy specimens but frequently are favored over larger bored needles because of their perceived safety. In order to minimize the chance of internal bleeding after a biopsy, external pressure is applied and patients are often asked to lie in uncomfortable positions, such as the lateral decubitus position, for a number of hours, particularly after a liver biopsy.
Sterile sponges, such as Gelfoam, are prepared in dry sterile sheets which are used as packing material during surgery for control of bleeding. The sponge sheets are left in the surgical site after surgery to stop bleeding and are absorbed by the body in one to six weeks. A number of techniques have used these absorbable sterile sponge materials to plug a biopsy tract to minimize or prevent bleeding. The absorbable sponge provides a mechanical blockage of the tract, encourages clotting, and minimizes bleeding though the biopsy tract. Despite the advantages of using an absorbable sponge to plug a biopsy tract this technique has not achieved widespread use because of difficulty in preparing and delivering the sponge material into the biopsy tract.
One example of a biopsy wound closure device using an implantable sponge is described in U.S. Pat. No. 5,388,588. According to this patent, a circular sponge of an absorbable foam material is precut and inserted into a biopsy site by an applicator rod having the sponge positioned on the end. Once the sponge is implanted, the sponge absorbs blood and swells to fill the tract preventing further bleeding at the biopsy site. However, the sponge is difficult to deliver and expands slowly once delivered. In addition, this delivery method can only deliver a sponge of a limited size which provides less local compression than desired and may incompletely fill the target site. Further, bleeding may continue along sections of the biopsy tract where no sponge has been delivered.
Accordingly, it would be desirable to provide a device, system and method for improving the delivery of hemostatic material by the use of a vent cap which restricts the flow of fluid through the vent cap.